NSFGEO-NERC: Stimulated Loss of Balance

pi最近获得的结果表明，近惯性波（NIWs）在中尺度气流中的平流和折射必然伴随着从中尺度向NIWs的能量转移：外部强迫NIWs的存在刺激了流的地转和静力平衡成分的能量损失。这一过程，即受刺激的平衡丧失（SLOB），应该与被研究得更多、更弱的自然平衡丧失（自发失去）过程进行对比。自发形式发生在1阶罗斯比数，没有外部强迫波。但即使在很小的罗斯比数下，受刺激的版本也很活跃，因此，我们假设，整个海洋都是如此。本提案的主要目标是评估和发展SLOB在中尺度能量收支中起主要作用的假设，并通过NIWs以外的内波谱成分，特别是内潮（IT）来研究SLOB。这将通过发展新的相平均模型来实现，该模型将内波的动力学与平衡中尺度流的动力学耦合，并通过这些模型和三维Boussinesq方程的数值解来实现。结果将是对SLOB在海洋能量收支中所起作用的定量理解。

Recent results obtained by the PIs show that the advection and refraction of near-inertial waves (NIWs) by mesoscale flow is necessarily accompanied by a transfer of energy from the mesoscale to NIWs: the presence of externally forced NIWs stimulates a loss of energy from the geostrophically and hydrostatically balanced component of the flow. This process, stimulated loss of balance (SLOB), should be contrasted with the much more studied and weaker process known as spontaneous loss of balance. The spontaneous version occurs at order one Rossby number and without externally forced waves. But the stimulated version is active even at small Rossby number and hence, we hypothesize, throughout the ocean. The main objectives of this proposal are to assess and develop the hypothesis that SLOB plays a major role in the mesoscale energy budget, and to investigate SLOB by components of the internal wave spectrum other than NIWs, particularly the internal tide (IT). This will be achieved by the development of new, phase-averaged models coupling the dynamics of internal waves with that of the balanced mesoscale flow, and through numerical solution of both these models and of the three-dimensional Boussinesq equations. The outcome will be a quantitative understanding of the role played by SLOB in the ocean energy budget.